Liquid crystal display device and method of manufacturing a liquid crystal display device

ABSTRACT

A liquid crystal display device, includes: a liquid crystal display panel having a first substrate and a second substrate with a display area and a non-display area; a backlight that irradiates the liquid crystal display panel with light; an adhesive layer that adheres the liquid crystal display panel to the backlight; a first polarizing plate stuck onto the first substrate; and a second polarizing plate stuck onto the second substrate, in which an outer edge of the second polarizing plate is located outside an outer edge of the second substrate, a light impermeable film and an alignment mark part are formed in the non-display area of the first substrate, and the light impermeable film and the alignment mark part are different in infrared transmittance or infrared reflectance.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Application JP2014-031367 filed on Feb. 21, 2014, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device and amethod of manufacturing the liquid crystal display device.

2. Description of the Prior Art

As a display device for information communication terminals such as acomputer and television receivers, liquid crystal display devices havinga backlight and a liquid crystal display panel have been extensivelyused. In recent years, the liquid crystal display devices are usedparticularly in cellular phones and smartphones. The liquid crystaldisplay devices need to be downsized, narrowed in frame, and simplifiedin a manufacturing process.

The liquid crystal display panel includes two substrates having adisplay area between which liquid crystal is confined, and a lowerpolarizing plate and an upper polarizing plate which are attached to therespective substrates. The liquid crystal display panel is fixed to thebacklight by an adhesive tape arranged on a lower surface of the lowerpolarizing plate. The liquid crystal display panel changes theorientation of liquid crystal molecules confined between the twosubstrates to change a transmission degree of a light irradiated fromthe backlight onto the liquid crystal display panel for displaying animage.

As the liquid crystal display device, for example, JP 2008-242193 Adiscloses a configuration in which a lower polarizing plate larger in aplanar view shape than the substrate is attached onto a lower surface ofthe substrate.

SUMMARY OF THE INVENTION

With the requirements for ensuring the display area, an area in whichthe adhesive tape is arranged is required to be arranged on an outsideas much as possible. However, if the area in which the adhesive tape isarranged is too small, an adhesion between the backlight and the liquidcrystal display panel is reduced.

In the liquid crystal display device disclosed in JP 2008-242193 A, theouter periphery of the lower polarizing plate is located outside theouter periphery of the substrate in a planar view. For that reason, theadhesive tape can be arranged outside the display area in a planar view.However, in the above liquid crystal display device, the outer peripheryof the lower polarizing plate is located outside the outer periphery ofthe substrate. For that reason, the outer periphery of the liquidcrystal display panel is aligned with the outer periphery of thebacklight to decrease a precision of positioning the display area andthe backlight. Also, in the liquid crystal display panel disclosed in JP2008-242193 A, the lower polarizing plate covers the overall lowersurface of the substrate. This leads to such a problem that alignmentwith the use of an alignment mark cannot be performed.

The present invention has been made in view of the above circumstances,and aims at realizing a method of manufacturing a liquid crystal displaydevice that can ensure a display area, and performs the alignment withhigh precision.

An outline of a typical feature of the invention disclosed in thepresent application will be described in brief below.

(1) According to the present invention, there is provided a liquidcrystal display device, including: a liquid crystal display panel havinga first substrate and a second substrate with a display area and anon-display area; a backlight that irradiates the liquid crystal displaypanel with light; an adhesive layer that adheres the liquid crystaldisplay panel to the backlight; a first polarizing plate stuck onto thefirst substrate; and a second polarizing plate stuck onto the secondsubstrate, in which an outer edge of the second polarizing plate islocated outside an outer edge of the second substrate, a lightimpermeable film and an alignment mark part are formed in thenon-display area of the first substrate, and the light impermeable filmand the alignment mark part are different in infrared transmittance orinfrared reflectance.

(2) According to the present invention, in the liquid crystal displaydevice according to the item (1), a color filter having a colored filmmay be disposed in the display area of the first substrate, and thecolored film may be formed in the alignment mark part.

(3) According to the present invention, in the liquid crystal displaydevice according to the item (1), a second alignment mark part differentin the infrared transmittance or infrared reflectance from the alignmentmark part may be formed inside the alignment mark part in a planar view.

(4) According to the present invention, there is provided a liquidcrystal display device, including: a liquid crystal display panel havinga first substrate and a second substrate with a display area and anon-display area; a backlight; an adhesive layer that adheres the liquidcrystal display panel to the backlight; a light impermeable film formedin the non-display area of the first substrate; an upper polarizingplate stuck onto the first substrate; and a lower polarizing plate stuckonto the second substrate, in which an outer edge of the lowerpolarizing plate is located outside an outer edge of the secondsubstrate, at least a part of the adhesive layer is arranged to overlapwith an area outside of the outer edge of the second substrate in aplanar view, and an opening is formed in the light impermeable film.

(5) According to the present invention, in the liquid crystal displaydevice according to the item (4), a colored film different in aninfrared transmittance or infrared reflectance from the lightimpermeable film may be formed within the opening.

(6) According to the present invention, in the liquid crystal displaydevice according to the item (4), the opening may be an alignment markpart.

(7) According to the present invention, in the liquid crystal displaydevice according to the item (5), a color filter having a colored filmmay be formed in the display area, and the colored film formed withinthe opening may be made of the same material as that of the colored filmof the color filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic planar view of a liquid crystal display deviceaccording to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of the liquid crystal displaydevice illustrated in FIG. 1 taken along a line II-II;

FIG. 3 is a partially enlarged view of an area III in the liquid crystaldisplay device illustrated in FIG. 1; and

FIG. 4 is a schematic cross-sectional view illustrating a method ofmanufacturing the liquid crystal display device according to thisembodiment in the same visual view as that of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a liquid crystal display device 1 according to thisembodiment will be described with reference to the accompanyingdrawings. The drawings referred to in the following description mayillustrate a characteristic part in an enlarged manner for theconvenience of understanding, and the ratio of the dimension of eachconstituent element may not be the same as the actual ratio. Materialsand the like exemplified in the following description are mere examplesand respective constituent elements may be different from them and maybe embodied by being changed in an extent that does not alter the gistthereof.

FIG. 1 is a schematic planar view of the liquid crystal display device 1according to an embodiment of the present invention, FIG. 2 is aschematic cross-sectional view taken along a line II-II of the liquidcrystal display device 1 illustrated in FIG. 1, and FIG. 3 is apartially enlarged view of an area III in the liquid crystal displaydevice 1 illustrated in FIG. 1.

First, a schematic configuration of the liquid crystal display device 1will be described. As illustrated in FIGS. 1 and 2, the liquid crystaldisplay device 1 according to this embodiment includes a backlight 20, aliquid crystal display panel 10 adhered over (in a Z1-direction of FIG.2) the backlight 20 with an adhesive layer 50, a flexible wiringsubstrate 2, and a driver IC 3. In this embodiment, for convenience ofdescription, a positional relationship of the respective configurationswill be described with the use of coordinates of an X-axis(X1-direction, X2-direction), a Y-axis (Y1-direction, Y2-direction), anda Z-axis (Z1-direction, Z2-direction).

For convenience of the description, the configuration of the backlight20 will be described prior to the configuration of the liquid crystaldisplay panel 10. The backlight 20 is a member that irradiates theliquid crystal display panel 10 with light. As illustrated in FIG. 2,the backlight 20 includes a reflection sheet 22, a frame 24, a lightguide plate 26, and an optical member 28.

The frame 24 is a member on which the adhesive layer 50 is arranged. Theframe 24 is formed of, for example, a molded frame-like resin. The frame24 is covered with a plate-like member not shown on a lower side(Z2-direction side of FIG. 2) thereof. With the above configuration, thereflection sheet 22, the light guide plate 26, the optical member 28,and light emitting elements not shown can be accommodated inside of theframe 24 and the plate-like member.

The reflection sheet 22 is a sheet that reflects a light input from thelight emitting elements toward the light guide plate 26 toward theliquid crystal display panel 10 side. The reflection sheet 22 isarranged to cover a lower side (Z2-direction side) of the light guideplate 26. The material of the reflection sheet 22 is not particularlylimited, but a material higher in optical reflectance is preferable, anda metal film made of, for example, aluminum is used.

The light guide plate 26 emits the light from the light emittingelements not shown from an upper surface 26 a thereof (a surface on theZ1-direction side of the light guide plate 26) toward a display area D.The light guide plate 26 is made of a transparent resin such as acrylic,but may be made of a material other than acrylic if the material hastranslucency.

The light emitting elements can be formed of, for example, lightemitting diodes. The light emitting elements are arranged on a sidesurface of the light guide plate 26 whereby the light emitted from thelight emitting elements is transferred to an interior of the light guideplate 26, and emitted from the upper surface 26 a. As a result, theupper surface 26 a of the light guide plate 26 functions as a surfacelight source.

The optical member 28 is arranged over the light guide plate 26(Z1-direction side). The optical member 28 controls the angulardistribution and diffusion of the light emitted from the upper surface26 a of the light guide plate 26. The optical member 28 is formed bylaminating plural optical sheets 28 a. The optical member 28 is disposedso as to cover the upper surface 26 a of the light guide plate 26.

With the above configuration, the light emitted from the upper surface26 a of the light guide plate 26 is transmitted to the liquid crystaldisplay panel 10 disposed over (Z1-direction side) the optical member 28through the optical member 28.

Then, the configuration of the liquid crystal display panel 10 will bedescribed. The liquid crystal display panel 10 is configured to controlthe transmittance of the light emitted from the backlight 20 to displaya desired image on a top surface thereof. As illustrated in FIG. 2, theliquid crystal display panel 10 is adhered over the backlight 20(Z1-direction) with the adhesive layer 50.

As illustrated in FIG. 2, the liquid crystal display panel 10 includes afirst substrate 12, liquid crystal not shown, a second substrate 14, afirst polarizing plate (upper polarizing plate 16), and a secondpolarizing plate (lower polarizing plate 18). Hereinafter, the detailsof the respective configurations will be described.

The first substrate 12 is, for example, a color filter substrate havinga glass substrate 112 and a color filter CF. With the use of the colorfilter substrate as the first substrate 12, the liquid crystal displaydevice 1 enables color display. The first substrate 12, as illustratedin FIGS. 1 and 2, has the display area D and a non-display area E.

In the display area D of the first substrate 12, the color filter CF isformed. The color filter CF includes a light impermeable (opaque) filmBM having a light shielding property such as a black matrix, which isdisposed on a lower surface (surface on the Z2-direction side) of theglass substrate 112 in a mesh, and colored films R, G, and B sectionedinto a matrix by the light impermeable film BM of the meshed shape. Thecolored films R, G, and B are higher in the light transmittance than thelight impermeable film BM, and higher in the transmittance of the lighthaving a particular wavelength than the light transmittance of otherwavelengths.

The colored films R, G, and B are made of resin colored with, forexample, a pigment. In this embodiment, in the colored films R, G, andB, for example, a red colored film R, a green colored film G, a bluecolored film B are formed according to each pixel.

The light impermeable film BM is formed in the non-display area E of thefirst substrate 12. For convenience of the description, the detailedconfiguration of the non-display area E will be described later.

The second substrate 14 is configured to hold liquid crystal between thesecond substrate 14 and the first substrate 12, and faces the firstsubstrate 12. The liquid crystal not shown is sealed between the firstsubstrate 12 and the second substrate 14. The second substrate 14 isformed of, for example, a TFT (thin film transistor) substrate. Thesecond substrate 14 is sectioned into the display area D and thenon-display area E outside of the display area D, and thin filmtransistors not shown are formed in the display area D.

The upper polarizing plate 16 is stuck onto an upper surface 12 a(surface on the Z1-direction side) of the first substrate 12. The lowerpolarizing plate 18 larger in a planar view shape than the secondsubstrate 14 is stuck onto a lower surface 14 a (surface on theZ2-direction side) of the second substrate 14. As illustrated in FIGS. 1and 2, an outer edge 18 b of the lower polarizing plate 18 is locatedoutside of an outer edge 14 b of the second substrate 14 in a planarview.

A lower surface 18 c (surface on the Z2-direction side) of the lowerpolarizing plate 18 is fixed over the backlight 20 (frame 24) with theadhesive layer 50. Also, the adhesive layer 50 is arranged to at leastpartially overlap with an area outside of the outer edge 14 b of thesecond substrate 14 in the planar view.

Specifically, as illustrated in FIG. 2, the adhesive layer 50 isarranged so that its outer edge (outer edge on the X2-direction side inFIG. 2) 50 b is located outside (on the X2-direction side in FIG. 2) ofthe outer edge 14 b of the second substrate 14. With this configuration,a part of the adhesive layer 50 overlaps with the lower polarizing plate18 in an area O outside of the outer edge 14 b of the second substrate14 in the planar view.

The liquid crystal display device 1 according to this embodiment isarranged in such a manner that the outer edge 18 b of the lowerpolarizing plate 18 is located outside of the outer edge 14 b of thesecond substrate 14, and at least a part of the adhesive layer 50overlaps with the area O outside of the outer edge 14 b of the secondsubstrate 14 in the planar view. With this configuration, as comparedwith the liquid crystal display device without this configuration, inthe liquid crystal display device 1 according to this embodiment, theadhesive layer 50 can be arranged in an area outside of the display areaD. For that reason, the liquid crystal display device 1 according tothis embodiment can widely ensure the display area D, and realize anarrow frame.

Also, as illustrated in FIGS. 1 and 2, in the liquid crystal displaydevice 1 according to this embodiment, an alignment mark part 40 may beformed in the non-display area E of the first substrate 12. Thealignment mark part 40 is a portion different in infrared transmittanceor infrared reflectance from the light impermeable film BM, and disposedinside of the light impermeable film BM in the planar view.

As illustrated in FIG. 3, the alignment mark part 40 according to thisembodiment is formed by forming a colored film 44 (R) within analignment mark opening 42 that exposes a lower surface of the glasssubstrate 112, which is formed in the light impermeable film BM. It ispreferable that the colored film 44 formed within the alignment markpart 40 has the same color as the red colored film R of the color filterCF.

The alignment mark opening 42 is formed by sputtering a material of thelight impermeable film BM with the use of, for example, a mask. In FIG.3, for convenience of the description, the upper polarizing plate 16 andthe glass substrate 112 are omitted from illustration.

In the alignment mark part 40, an inside portion of the alignment markopening 42 in the planar view may be different in the infraredtransmittance or infrared reflectance from the light impermeable filmBM. For example, an inside of the alignment mark opening 42 may befilled with a transparent resin. Also, nothing may be formed on theinside portion of the alignment mark opening 42.

In the liquid crystal display device 1 according to this embodiment,with the formation of the alignment mark part 40 in the non-display areaE, even if the outer edge 18 b of the lower polarizing plate 18 isconfigured to be located outside of the outer edge 14 b of the secondsubstrate 14, the liquid crystal display panel 10 may be aligned withthe backlight 20 with high precision.

The infrared transmittance or infrared reflectance of the alignment markpart 40 is different from the infrared transmittance or infraredreflectance of the light impermeable film BM. For that reason, when theupper polarizing plate 16 is irradiated with infrared rays from above,and observed by, for example, a CCD camera, a boundary (alignment markopening 42) between the alignment mark part 40 and the light impermeablefilm BM can be visually recognized.

In the liquid crystal display device 1 according to this embodiment, theliquid crystal display panel 10 and the backlight 20 are aligned witheach other with the use of the alignment mark part 40. For that reason,as compared with the liquid crystal display device without thisconfiguration, the alignment is performed inexpensively. For thatreason, the liquid crystal display device 1 low in the costs can beprovided.

It is preferable that a planar view shape of the alignment mark isformed in a cross shape as illustrated in FIG. 3. Since the planar viewshape of the alignment mark part 40 is a cross-shaped, the position ofthe alignment mark part 40 is likely to be accurately visuallyrecognized. In addition, the planar view shape of the alignment markpart 40 is not limited to the cross shape, but may be formed in othershapes such as a linear, rectangular or ring shape.

The size of the alignment mark part 40 is not particularly limited, butpreferably as small as possible within a range visibly recognizable withthe use of the camera. The alignment mark part 40 according to thisembodiment is, for example, 150 μm in width d1 in an X-direction and aY-direction, and 50 μm in length d2 of short sides.

As illustrated in FIG. 3, it is preferable that the alignment mark part40 is formed with a second alignment mark part 46 different in theinfrared transmittance or infrared reflectance from the alignment markpart 40 on the inside thereof in the planar view. The planar view shapeof the second alignment mark part 46 in this embodiment is a cross shapesmaller than the alignment mark part 40. The planar view shape of thesecond alignment mark part 46 may be other shapes if the alignment markopening 42 can be visibly recognized in the planar view.

The second alignment mark part 46 in this embodiment is obtained bysputtering a material of the light impermeable film BM, for example,with the use of a mask. The material of the second alignment mark part46 is not limited to the light impermeable film BM. The second alignmentmark part 46 may be made of other materials if the second alignment markpart 46 is made of a material different in the infrared transmittance orinfrared reflectance of the alignment mark part 40 (area inside of thealignment mark opening 42).

In the liquid crystal display device 1 according to this embodiment, thesecond alignment mark part 46 different in the infrared transmittance orinfrared reflectance from the alignment mark part 40 is formed inside ofthe alignment mark part 40 in the planar view. For that reason, ascompared with the liquid crystal display device without thisconfiguration, the liquid crystal display panel 10 and the backlight 20are aligned with each other with high precision.

In addition, it is preferable that the alignment mark parts 40, asillustrated in FIG. 1, are formed at least two places at least alonglong sides of the outer edge 18 b of the lower polarizing plate 18. Therespective alignment mark parts 40 in this embodiment are formed in thevicinity of both ends of the outer edge 18 b extending in theY-direction. Also, as illustrated in FIG. 1, the alignment mark parts 40may be located on a diagonal line on the outer edge 18 b of the lowerpolarizing plate 18.

Next, a method of manufacturing the liquid crystal display device 1according to the embodiment of the present invention will be describedwith reference to FIG. 4. FIG. 4 is a schematic cross-sectional viewillustrating a method of manufacturing the liquid crystal display device1 according to this embodiment in the same visual field as that of FIG.2.

The method of manufacturing the liquid crystal display device 1illustrated in FIGS. 1 and 2 includes a step of providing the backlight20, a step of providing the liquid crystal display panel 10, and anadhesion step of adhering the backlight 20 and the liquid crystaldisplay panel 10 with the adhesive layer 50. Hereinafter, thoserespective steps will be described in detail.

First, the backlight 20 is prepared. As illustrated in FIG. 4, thebacklight 20 includes the reflection sheet 22, the frame 24, the lightguide plate 26, and the optical member 28.

The light emitting elements not shown are arranged on a side surface ofthe light guide plate 26. With this configuration, the upper surface 26a of the light guide plate 26 functions as a surface light source. Theoptical member 28 is formed by laminating the plural optical sheets 28a. The optical member 28 is arranged to cover the upper surface 26 a ofthe light guide plate 26.

Then, the liquid crystal display panel 10 is prepared. As illustrated inFIG. 4, the liquid crystal display panel 10 according to this embodimentincludes the first substrate 12, the liquid crystal not shown, thesecond substrate 14, the upper polarizing plate 16, and the lowerpolarizing plate 18.

The first substrate 12 includes the display area D and the non-displayarea E. The display area D is formed with the color filter CF having,for example, the red colored film R, the green colored film G, and theblue colored film B. The respective colored films R, G, and B aresectioned in a matrix by the light impermeable film BM.

The non-display area E of the first substrate 12 is formed with thelight impermeable film BM, and the alignment mark part 40 different ininfrared transmittance or infrared reflectance from the lightimpermeable film BM. For convenience of description, the detailedconfiguration of the alignment mark part 40 will be described later.

The second substrate 14 faces the first substrate 12. The liquid crystalnot shown is sandwiched between the second substrate 14 and the firstsubstrate 12.

The upper surface 12 a of the first substrate 12 is stuck with the upperpolarizing plate 16. The lower surface 14 a of the second substrate 14is stuck onto the lower polarizing plate 18 larger in the planar viewshape than the second substrate 14. As illustrated in FIG. 4, the outeredge 18 b of the lower polarizing plate 18 is located outside(X2-direction side) of the outer edge 14 b of the second substrate 14.

Next, the detailed configuration of the non-display area E of the firstsubstrate 12 will be described. It is preferable that, as illustrated inFIG. 3, the alignment mark part 40 formed on the light impermeable filmBM is formed by forming the colored film 44 within the alignment markopening 42 in which a part of the light impermeable film BM is removed.

The alignment mark opening 42 is formed by sputtering a material of thelight impermeable film BM with the use of a mask having a desired planarview shape, for example, in forming the light impermeable film BM in thedisplay area D and the non-display area E.

It is preferable that the colored film 44 formed within the alignmentmark opening 42 has the same color (red in this embodiment) as that ofthe colored film R of the color filter CF. However, the colored film 44may be other colors such as colorless. Also, in the alignment mark part40, the inside portion of the alignment mark opening 42 may be differentin infrared transmittance or infrared reflectance from the lightimpermeable film BM. For example, nothing may be formed inside of thealignment mark opening 42.

It is preferable that the planar view shape of the alignment mark part40 is a cross shape as illustrated in FIG. 3. The planar view shape ofthe alignment mark part 40 is not limited to the cross shape, but may beother shapes such as a linear, rectangular, or circular shape.

As illustrated in FIG. 3, it is preferable that the alignment mark part40 is formed with the second alignment mark part 46 different ininfrared transmittance or infrared reflectance from the alignment markpart 40 on the inside thereof in the planar view. The planar view shapeof the second alignment mark part 46 in this embodiment may be a crossshape smaller than the alignment mark part 40, but may be other shapes.

The second alignment mark part 46 in this embodiment is formed bysputtering the light impermeable film BM with the use of, for example, amask. The material of the second alignment mark part 46 is not limitedto the light impermeable film BM, but may be other materials if thesecond alignment mark part 46 is made of a material different ininfrared transmittance or infrared reflectance from the alignment markpart 40 (area inside of the alignment mark opening 42).

In addition, it is preferable that the alignment mark parts 40, asillustrated in FIG. 1, are formed in at least two places at least alongthe long sides of the outer edge 18 b of the lower polarizing plate 18.The respective alignment mark parts 40 in this embodiment are formed inthe vicinity of both ends of the outer edge 18 b extending in theY-direction. Also, as illustrated in FIG. 1, the alignment mark parts 40may be located on a diagonal line of the outer edge 18 b of the lowerpolarizing plate 18.

Next, an adhesion process of adhering the backlight 20 and the liquidcrystal display panel 10 to each other with the adhesive layer 50 willbe described in detail. First, at least a part of the adhesive layer 50is arranged to overlap with the area outside of the outer edge 14 b ofthe second substrate 14 on the backlight 20 in the planar view.

As illustrated in FIG. 4, specifically, when the backlight 20 adheres tothe liquid crystal display panel 10, the adhesive layer 50 is arrangedon the frame 24 in advance so that the outer edge (outer edge on theX2-direction side in FIG. 2) 50 b of the adhesive layer 50 is locatedoutside (X2-direction side) of the outer edge 14 b of the secondsubstrate 14.

With the above configuration, a part of the adhesive layer 50 overlapswith the lower polarizing plate 18 in the area O outside of the outeredge 14 b of the second substrate 14 in the planar view.

Then, the backlight 20 is aligned with the liquid crystal display panel10. First, as illustrated in FIG. 4, the liquid crystal display panel 10is arranged between a camera C that can sense infrared rays and thebacklight 20 which are fixed at given positions. The camera C may be,for example, a CCD camera.

For example, an observer visually recognizes the position of thealignment mark part 40 by the camera C while the liquid crystal displaypanel 10 is irradiated with the infrared rays from above (Z1-direction).

In this situation, the infrared rays with which the liquid crystaldisplay panel 10 is irradiated from above are transmitted through theupper polarizing plate 16 and the glass substrate 112 to reach thealignment mark part 40 and the light impermeable film BM. The innerportion of the alignment mark opening 42 (in this embodiment, thecolored film 44(R)) is different in infrared transmittance or infraredreflectance from the light impermeable film BM. For that reason, thealignment mark opening 42 which is the boundary between the colored film44 and the light impermeable film BM can be visually recognized by theobserver.

In addition, it is preferable that the planar view shape of thealignment mark part 40 is cross. The alignment mark part 40 having thecross planar view shape includes an intersection portion of tworectangles (a center portion 40 a of the alignment mark part 40), andportions (line segment portions 40 b of the alignment mark part 40)outside of the center portion 40 a.

Also, it is preferable that the second alignment mark part 46 is formedinside of the alignment mark part 40. It is preferable that the planarview shape of the second alignment mark part 46 is a cross. The secondalignment mark part 46 having the cross planar view shape includes anintersection portion (a center portion 46 a of the second alignment markpart 46) of two rectangles, and portions (line segment portions 46 b ofthe second alignment mark part 46) outside of the center portion 46 a.

The second alignment mark part 46 is different in infrared transmittanceor infrared reflectance from the alignment mark part 40 (colored film 44which is a portion inside of the alignment mark opening 42). For thatreason, as illustrated in FIG. 3, a boundary 48 between the colored film44 and the second alignment mark part 46 can be visually recognized withthe irradiation of the infrared rays by the observer.

With the irradiation of the liquid crystal display panel 10 with theinfrared rays, the observer can visually recognize the alignment markpart 40 through the upper polarizing plate 16 by the camera C. As aresult, the observer can align the liquid crystal display panel 10.

In this case, the observer observes images taken by the camera C, and asillustrated in FIG. 3, positions the liquid crystal display panel 10 sothat the center of the alignment mark part 40 is aligned with a givenposition of the screen. If the planar view shape of the alignment markpart 40 is a cross, it is preferable to perform alignment so as tolocate the center portion 40 a at the given position on the screen.Also, the alignment may be performed so that the line segment portions40 b are located at the given position on the screen.

When the second alignment mark part 46 is formed inside of the alignmentmark part 40, it is preferable that the alignment is performed so thatthe center portion 46 a of the second alignment mark part 46 is locatedat the given position on the screen, as illustrated in FIG. 3.Alternatively, the alignment may be performed so that the line segmentportions 46 b are located at the given position on the screen.

After the alignment of the liquid crystal display panel 10 has been thusperformed, the liquid crystal display panel 10 moves down (Z2-directionindicated in FIG. 4), and the lower surface (lower surface 18 c of thelower polarizing plate 18) of the liquid crystal display panel 10 isadhered to the adhesive layer 50. As a result, the liquid crystaldisplay panel 10 is adhered to the backlight 20 with the adhesive layer50.

Thereafter, with the provision of the flexible wiring substrate 2 andthe driver IC 3, the liquid crystal display device 1 illustrated inFIGS. 1 and 2 is manufactured.

In the method of manufacturing the liquid crystal display device 1according to this embodiment, the outer edge 18 b of the lowerpolarizing plate 18 is located outside of the outer edge 14 b of thesecond substrate 14, and the adhesive layer 50 is arranged so that atleast a part of the adhesive layer 50 overlaps with the area O outsideof the outer edge 14 b of the second substrate 14 in the planar view. Asa result, as compared with the liquid crystal display device withoutthis configuration, the adhesive layer 50 can be arranged in the outsidearea. Specifically, the outer edge 50 b of the adhesive layer 50 islocated outside (X2-direction side) of the outer edge 14 b of the secondsubstrate 14.

For that reason, the method of manufacturing the liquid crystal displaydevice 1 according to this embodiment can provide the liquid crystaldisplay device 1 that can ensure the display area D widely, and canrealize a narrow frame.

Also, in the method of manufacturing the liquid crystal display device 1according to this embodiment, since the alignment mark part 40 formed inthe non-display area E is irradiated with infrared rays, even in theconfiguration where the outer edge 18 b of the lower polarizing plate 18is located outside of the outer edge 14 b of the second substrate 14,the liquid crystal display panel can be aligned while the alignment markpart 40 is visually recognized. For that reason, the liquid crystaldisplay panel 10 can be aligned with the backlight 20 with highprecision.

Also, in the method of manufacturing the liquid crystal display device 1according to this embodiment, since the alignment mark part 40 has thealignment mark opening 42 formed by removing a part of the lightimpermeable film BM, the alignment mark opening 42 can be formed in thenon-display area E at the same time when forming the light impermeablefilm BM.

Also, in the method of manufacturing the liquid crystal display device 1according to this embodiment, the colored film 44 is formed within thealignment mark opening 42 at the same time when forming the coloredfilms R, G, and B in the display area D. As a result, the alignment markpart 40 can be formed at the same time when forming the color filter CFin the display area D. For that reason, there can be provided theinexpensive liquid crystal display device 1 that can obtain theadvantages of the present invention without any increase in theprocesses and the costs.

Also, in this embodiment, since the alignment mark part 40 having thecross planar view shape is formed, the observer can align the liquidcrystal display panel 10 while recognizing an allowable range (linesegment portions 40 b) of the position of the alignment mark part 40,and the preferable position (center portion 40 a). For that reason, ascompared with the manufacturing method without this configuration, aprecision in the alignment of the liquid crystal display panel 10 can beenhanced.

Also, in this embodiment, the second alignment mark part 46 is formedinside of the alignment mark part 40 in the planar view. As a result,the liquid crystal display panel 10 can be aligned with the backlight 20with the use of the second alignment mark part 46 in addition to thealignment mark part 40. For that reason, as compared with the method ofmanufacturing the liquid crystal display device without thisconfiguration, the alignment higher in precision can be realized.

Also, in this embodiment, since the planar view shape of the secondalignment mark part 46 is a cross, the observer can align the liquidcrystal display panel 10 while recognizing the allowable range (linesegment portions 46 b) of the position of the second alignment mark part46, and the preferable position (center portion 46 a). For that reason,as compared with the manufacturing method without this configuration, aprecision in the alignment of the liquid crystal display panel 10 can beenhanced.

Also, in this embodiment, since the red colored film R is formed withinthe alignment mark opening 42, with the irradiation of the infraredrays, the alignment mark part 40 can be easily visually recognized.

The embodiments of the present invention have been described above.However, the present invention is not limited to the above embodiments.For example, the configurations described in the above embodiments maybe replaced with substantially identical configurations, configurationshaving the same effects, or configurations that can achieve the samepurpose.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaim cover all such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. A liquid crystal display device, comprising: aliquid crystal display panel having a first substrate and a secondsubstrate with a display area and a non-display area; a backlight thatirradiates the liquid crystal display panel with light; an adhesivelayer that adheres the liquid crystal display panel to the backlight; afirst polarizing plate stuck onto the first substrate; and a secondpolarizing plate stuck onto the second substrate, wherein an outer edgeof the second polarizing plate is located outside an outer edge of thesecond substrate, the second polarizing plate has a protruding portionextending from the outer edge of the second substrate to the outer edgeof the second polarizing plate, the protruding portion of the secondpolarizing plate being fixed to the backlight with the adhesive layer, alight impermeable film and an alignment mark part are formed in thenon-display area of the first substrate and are covered with the firstpolarizing plate, and the light impermeable film and the alignment markpart are different in infrared transmittance or infrared reflectance. 2.The liquid crystal display device according to claim 1, wherein a colorfilter having a colored film is disposed in the display area of thefirst substrate, and the colored film is formed in the alignment markpart.
 3. The liquid crystal display device according to claim 1, whereina second alignment mark part different in the infrared transmittance orinfrared reflectance from the alignment mark part is formed inside thealignment mark part in a planar view.
 4. A liquid crystal displaydevice, comprising: a liquid crystal display panel having a firstsubstrate and a second substrate with a display area and a non-displayarea; a backlight; an adhesive layer that adheres the liquid crystaldisplay panel to the backlight; an opaque film formed in the non-displayarea of the first substrate; an upper polarizing plate stuck onto thefirst substrate; and a lower polarizing plate stuck onto the secondsubstrate, wherein an outer edge of the lower polarizing plate islocated outside an outer edge of the second substrate, the lowerpolarizing plate has a protruding portion extending from the outer edgeof the second substrate to the outer edge of the lower polarizing plate,the protruding portion of the lower polarizing plate being fixed to thebacklight with the adhesive layer, at least a part of the adhesive layeris arranged to overlap with an area outside of the outer edge of thesecond substrate in a planar view, and an opening is formed in theopaque film and overlapped with the upper polarizing plate.
 5. Theliquid crystal display device according to claim 4, wherein a coloredfilm different in an infrared transmittance or infrared reflectance fromthe opaque film is formed within the opening.
 6. The liquid crystaldisplay device according to claim 4, wherein the opening is an alignmentmark part.
 7. The liquid crystal display device according to claim 5,wherein a color filter having a colored film is formed in the displayarea, and the colored film formed within the opening is made of the samematerial as that of the colored film of the color filter.